Engine systems may include one or more turbochargers or other turbine-based systems. In some examples, turbocharger systems may include two turbochargers configured in series, such as a high pressure turbocharger fluidically coupled to a low pressure turbocharger. To control the boost pressure generated by the high pressure compressor, a bypass valve upstream from the high pressure turbine may be utilized to divert and bypass exhaust flow around the high pressure turbine. In one example, the diverted or bypass flow may be routed around the high pressure turbine and reintroduced into the exhaust flow downstream of the high pressure turbine and upstream from the low pressure turbine.
In some prior configurations that have routed bypass flow around a high pressure turbine, a bifurcated pipe joint or other branch has been utilized to reintroduce the bypass flow into the exhaust flow upstream of a low pressure turbine. Such joints or branches have also been utilized to extract fluid from and/or inject fluid into other engine systems and conduits such as, for example, exhaust gas regeneration (EGR) systems, compressor bypass systems, etc.
Bifurcated pipe joints or branches typically inject the bypass flow into the main flow, or extract a portion of the main flow, at a single discrete location along the circumference of the main flow conduit. In this manner, however, such joints and branches may also create local flow disturbances within the main flow. Such flow disturbances can lead to undesirable boundary layer separation, pressure losses, and/or non-uniform flow within the main flow. These configurations may also provide less than desirable flow mixing between the bypass or reintroduced flow and the main flow. Additionally, such configurations may also increase the packaging volume required for the turbocharger or other system within the associated engine.